<!DOCTYPE html>
<style>
html { writing-mode: vertical-rl; }
body > div { height: 15em; width: 10em; margin: 1em; padding: 2px; border: 1px solid silver; }
div > div { margin: .5em; padding: .5em; background: yellow; }
.a { clear: inline-start; }
.b { clear: inline-end; }
.is { float: inline-start; width: 4em; }
.ie { float: inline-end; width: 2em; }
.ltr { direction: ltr; }
.rtl { direction: rtl; }
</style>

<body>
<div class="ltr">
 <div class="is">Start</div>
 <div class="ie">End</div>
 <p class="a">a b c d e f g h i j k l m n o p q r s t u v w x y z LTR clear:inline-start</p>
</div>

<div class="ltr">
 <div class="is">Start</div>
 <div class="ie">End</div>
 <p class="b">a b c d e f g h i j k l m n o p q r s t u v w x y z LTR clear:inline-end</p>
</div>

<div class="rtl">
 <div class="is">Start</div>
 <div class="ie">End</div>
 <p class="a">a b c d e f g h i j k l m n o p q r s t u v w x y z RTL clear:inline-start</p>
</div>

<div class="rtl">
 <div class="is">Start</div>
 <div class="ie">End</div>
 <p class="b">a b c d e f g h i j k l m n o p q r s t u v w x y z RTL clear:inline-end</p>
</div>
